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Preparing cuprous oxide nanomaterials by electrochemical method for non-enzymatic glucose biosensor
Nguyen, Thu-Thuy,Huy, Bui The,Hwang, Seo-Young,Vuong, Nguyen Minh,Pham, Quoc-Thai,Nghia, Nguyen Ngoc,Kirtland, Aaron,Lee, Yong-Ill IOP 2018 Nanotechnology Vol.29 No.20
<P>Cuprous oxide (Cu<SUB>2</SUB>O) nanostructure has been synthesized using an electrochemical method with a two-electrode system. Cu foils were used as electrodes and NH<SUB>2</SUB>(OH) was utilized as the reducing agent. The effects of pH and applied voltages on the morphology of the product were investigated. The morphology and optical properties of Cu<SUB>2</SUB>O particles were characterized using scanning electron microscopy, x-ray diffraction, and diffuse reflectance spectra. The synthesized Cu<SUB>2</SUB>O nanostructures that formed in the vicinity of the anode at 2 V and pH?=?11 showed high uniform distribution, small size, and good electrochemical sensing. These Cu<SUB>2</SUB>O nanoparticles were coated on an Indium tin oxide substrate and applied to detect non-enzyme glucose as excellent biosensors. The non-enzyme glucose biosensors exhibited good performance with high response, good selectivity, wide linear detection range, and a low detection limit at 0.4 <I>μ</I>M. Synthesized Cu<SUB>2</SUB>O nanostructures are potential materials for a non-enzyme glucose biosensor.</P>
Nguyen Hoang Linh,Nguyen Minh Son,Tran The Quang,Nguyen Van Hoi,Vuong Thanh,Do Van Truong Materials Research Society of Korea 2023 한국재료학회지 Vol.33 No.5
This study uses first-principles calculations to investigate the mechanical properties and effect of strain on the electronic properties of the 2D material 1H-PbX<sub>2</sub> (X: S, Se). Firstly, the stability of the 1H Pb-dichalcogenide structures was evaluated using Born's criteria. The obtained results show that the 1H-PbS<sub>2</sub> material possesses the greatest ideal strength of 3.48 N/m, with 3.68 N/m for 1H-PbSe<sub>2</sub> in biaxial strain. In addition, 1H-PbS<sub>2</sub> and 1H-PbSe<sub>2</sub> are direct semiconductors at equilibrium with band gaps of 2.30 eV and 1.90 eV, respectively. The band gap was investigated and remained almost unchanged under the strain ε<sub>xx</sub> but altered significantly at strains ε<sub>yy</sub> and ε<sub>bia</sub>. At the fracture strain in the biaxial direction (19 %), the band gap of 1H-PbS<sub>2</sub> decreases about 60 %, and that of 1H-PbSe<sub>2</sub> decreases about 50 %. 1H-PbS<sub>2</sub> and 1H-PbSe<sub>2</sub> can convert from direct to indirect semiconductor under the strain ε<sub>yy</sub>. Our findings reveal that the two structures have significant potential for application in nanoelectronic devices.
Vuong, Nguyen Minh,Jung, Hyuck,Kim, Dojin,Kim, Hyojin,Hong, Soon-Ku The Royal Society of Chemistry 2012 Journal of materials chemistry Vol.22 No.14
<P>Here, we used NO as a test gas to propose a strategy for a nanowire gas sensor with the maximum response—the lowest detection limits. The apparatus uses an open space ensemble structure of nanowires with diameters at near total-depletion. For this purpose, a series of open space nanowire structures of WO<SUB>3</SUB> was fabricated with diameters varying from 35 to 82 nm, and a corresponding conduction nanowire sensor model was proposed. The nanowire structures revealed the highest response and a lowest detection limit of 30 ppb. Furthermore, the sensor response was maximum with nanowires of ∼40 nm, which is the diameter corresponding to total depletion conditions; the response was decreased at smaller diameters. The sensor model successfully explained the ultimate lower limits of the size effect in the nanowire sensors. To realize optimum sensor performance with the practical ensemble type nano-structures, an open space morphology is critical to remove the effect of gas diffusion throughout the structure.</P> <P>Graphic Abstract</P><P>High porosity is a requirement to high performance of nanowire-ensemble sensors whose resistances are controlled by the surface depletion mechanism. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c2jm15971f'> </P>
Optic foramen location on computed tomography
Vuong Duc Nguyen,Minh Tran Quang Le,Chuong Dinh Nguyen,Tho Thi Kieu Nguyen Korean Cleft Palate-Craniofacial Association 2023 Archives of Craniofacial Surgery Vol.24 No.4
Background: This study aimed to identify the location of the optic foramen in relation to the anterior sphenoid sinus wall, which is essential information for surgeons in planning and performing endoscopic transnasal surgery. Methods: Computed tomography scans of 200 orbits from 100 adult patients with no abnormalities were examined. The results included the location of the optic foramen in relation to the anterior sphenoid sinus wall and the distance between them, as well as the distance from the optic foramen and the anterior sphenoid sinus wall to the carotid prominence in the posterior sphenoid sinus. Results: The optic foramen was anterior to the anterior sphenoid sinus wall in 48.5% of orbits, and posterior in the remaining 51.5%. The mean distance from the optic foramen to the anterior sphenoid sinus wall was 3.82±1.25 mm. The mean distances from the optic foramen and the anterior sphenoid sinus wall to the carotid prominence were 7.67±1.73 and 7.95±2.53 mm, respectively. Conclusion: The optic foramen was anterior to the anterior wall of the sphenoid sinus in approximately half of the orbits examined in this study, and posterior in the remaining half. The mean distance from the optic foramen to the anterior sphenoid sinus wall of the sphenoid sinus was 3.82±1.25 mm.
Vuong, Nguyen Minh,Reynolds, John Logan,Conte, Eric,Lee, Yong-Ill American Chemical Society 2015 The Journal of Physical Chemistry Part C Vol.119 No.43
<P>We report a promising simple strategy for improving the performance of the photoanode for photoelectrochemical (PEC) water splitting. ZnO nanorods on an indium tin oxide glass substrate were synthesized by a hydrothermal method following calcinations in air at 500 °C for 2 h and pure ambient hydrogen at atmospheric pressure at 400 °C for 30 min. The hydrogenated ZnO (H:ZnO) sample shows an enhanced photocurrent in comparison to that of ZnO nanorods. To enhance the absorption in the visible light and near-infrared regions, H:ZnO nanorods were sensitized by cadmium sulfide (CdS) nanoparticles and carbon quantum dots (CQDs). The H:ZnO nanorod film sensitized in this way exhibited significantly improved PEC properties after treatment with ambient nitrogen at 400 °C for 30 min. The optimized H:ZnO nanorod sample sensitized by CdS and CQDs yields a photocurrent density of ∼12.82 mA/cm<SUP>2</SUP> at 0 V (vs saturated calomel electrode (SCE)) in 0.25 M Na<SUB>2</SUB>S and 0.35 M Na<SUB>2</SUB>SO<SUB>3</SUB> solution under the illumination of simulated solar light (100 mW/cm<SUP>2</SUP> from a 150 W xenon Arc lamp source). The optimal structure shows a solar-to-hydrogen conversion efficiency of ∼3.85% (at −0.67 V vs SCE). The H<SUB>2</SUB> gas generation obtained using this optimal structure consisting of H:ZnO nanorods sensitized by CdS and CQDs was 7.04 mL/cm<SUP>2</SUP> in 1 h. The morphology and properties of the samples were examined by scanning electron microscopy, X-ray diffraction, transmission electron microscopy, ultraviolet–visible absorption, and electrical measurements.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jpccck/2015/jpccck.2015.119.issue-43/acs.jpcc.5b08724/production/images/medium/jp-2015-08724e_0008.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/jp5b08724'>ACS Electronic Supporting Info</A></P>
Nguyen Thi Minh Nguyet,Le Van Thang,Nguyen Huu HuyPhuc,Vinh-Dat Vuong,Tran Van Khai,Mai Thanh Phong 한양대학교 세라믹연구소 2019 Journal of Ceramic Processing Research Vol.20 No.2
MoS2 nanosheets (NS) were directly grown on carbon nanofiber (CF) and employed as electrocatalyst for hydrogen evolutionreaction (HER). The structural, surface morphology and chemical composition of the nanocomposites were characterized byfield emission scanning electron microscopy (FE-SEM), high-resolution transmission electron microscopy (HR-TEM), energydispersiveX-ray spectroscopy (EDS), X-ray diffraction (XRD), and Raman spectroscopy. XRD and TEM-EDS measurementsshowed that the molybdenum oxide precursor was successfully transferred into MoS2 nanosheets. It was confirmed from FESEMand TEM images that NS was uniformly distribution on surface of the CF. The HR-TEM images disclosed that the NSwas formed perpendicular to surface of CF fibers via the MoS2 layers growth parallel to CF surface which act as interface. The HER current density was about 12 mA cm−2 at catalyst loading of only 60 μg cm−2 at -0.384 V (vs. RHE).
SnO<sub>2</sub> Hollow Hemisphere Array for Methane Gas Sensing
Hieu, Nguyen Minh,Vuong, Nguyen Minh,Kim, Dojin,Choi, Byung Il,Kim, Myungbae Materials Research Society of Korea 2014 한국재료학회지 Vol.24 No.9
We developed a high-performance methane gas sensor based on a $SnO_2$ hollow hemisphere array structure of nano-thickness. The sensor structures were fabricated by sputter deposition of Sn metal over an array of polystyrene spheres distributed on a planar substrate, followed by an oxidation process to oxidize the Sn to $SnO_2$ while removing the polystyrene template cores. The surface morphology and structural properties were examined by scanning electron microscopy. An optimization of the structure for methane sensing was also carried out. The effects of oxidation temperature, film thickness, gold doping, and morphology were examined. An impressive response of ~220% was observed for a 200 ppm concentration of $CH_4$ gas at an operating temperature of $400^{\circ}C$ for a sample fabricated by 30 sec sputtering of Sn, and oxidation at $800^{\circ}C$ for 2 hr in air. This high response was enabled by the open structure of the hemisphere array thin films.